Apparatus for the extraction of glue, gelatin, and the like



F. H. TUNNELL.

APPARATUS FOR THE EXTRACTION 0F GLUE, GELATIN, AND THE LIKE APPLICATION FILED DEC.10, I920} v Patented July 4, 1922.

INVENTOR Milan/Z611.

,, Mv/w ATTORNEYS- EREDERIC H. TUNNELL, OF PHILADELPHIA, PENNSYLVANIA.

raercec.

Specification of Letters Patent.

Patented July 42, 1922.

Application. filed December 10, 1920. Serial No. 429,608.

To all whom it may concern:

Be it known that l, Fnuonnr H. TUNNELL, a citizen of the United States, and a resident of the city of Philadelphia, county of Philadelphia, and State of Pennsylvania, have invented a certain new and useful Apparatus for the Extraction of Glue, Gelatin, and the like, of which the following a specification, reference being had to the accompanying drawing.

In my pending application for Letters Patent of the United States, Serial No. 307,369, filed June 28, 1919, allowed November 3, 1920, l disclosed and claimed a process and apparatus for the extraction of glue, gelatin and the like from the usual materials employed for that purpose and commercially known as glue stock, in which a cyclic circulation of a glue extracting liquid in intimate contact with a mass of glue yielding material is effected by local heating. This process operates very satisfactorily with numerous grades of glue stock and results in the production of glue of quality improved over that extracted by other processes known and utilized prior to my said invention. However, it is well known that in the extraction of glue it is desirable in order to produce a glue of high commercial quality to keep the temperature of the glue stock and extracting-liquid at a relatively low point during the extraction process and that with numerous kinds and grades of glue stock satisfactory results may be obtained when the temperature is kept as low as l-l-O l. and possibly lower. 0n the other hand, obviously a reduction in the temperature effects a corresponding increase in the length of time necessary to effect the extraction of the glue from a given batch of stock. and l have found in practice that the process forming the subject of my said application cannot ordinarily be operated satisfactorily and within the time limits requisite in commercial use if the temperature of the extracting liquid is maintained much below the boiling point. to wit. 212 F. as at lower temperatures the cyclic circulation referred to is not effected with the requisite rapidity.

l have found, however, .in practice, that by the utilization of suitable means, inreferably in the form of an air jet, adjacent the ease of the column of ascending glue extracting liquid, the upward flow thereof may be accelerated and the requisite rapidity of circulation effected while maintaining the temperature of the extracting liquid at a much lower point than is possible when local heating alone is relied on to effect the circulatlon, so that by the use of my improved process the extraction may be effected at temperatures materially below the boiling point and yet with a sufficient rapidity to render the process commercially practical.

One of the objects of my invention, therefore, is to provide a process and an apparatus adapted for the performance thereof by the use of which the extraction of glue or gelatin may be effected at relatively low temperatures and without the necessity for mechanical agitation, the glue thus produced being improved in adhesive or binding strength. practically free from foam or froth due to the presence of lime soaps and of better color and transparency than glue produced from similar grades of stock by other methods.

Moreover, similarly to the process the subject of my said application, the use of the present process results in the extraction of a maximum yield of glue or gelatin from a given weight of any class of glue stock, as well as in increased economies in manufacture from the avoidance of the necessity of mechanical agitation and also in a saving of steam or other heating medium utilized.

The present invention further includes all of the other various novel steps, features, characteristics, objects and advantages to which reference will hereinafter be made.

In carrying out my improved process for the extraction of glue, gelatin and the like I may employ any suitable apparatus, but have found in practice that an apparatus constructed substantially as hereinafter described and as shown in the accompanying drawing in which the said apparatus is illustrated somewhat diagrammatically, Fig. 1 showing the same partially in central vertical section and partially in elevation, and Fig. 2 being a fragmentary horizontal section taken 011 line 2-2 of Fig. 1 looking in the direction of the arrows, is well adapted for the purposes intended. However, if desired other suitable forms of apparatus may be employed for carrying out the process.

Referring to the drawing, the apparatus shown therein may comprise a suitable tank fl. of metal. wood or other material, preferably of circular transverse section with slightly diverging side walls whereby the diameter of the tank is increased toward the top which is left entirely open. The tank may be supported on suitable beams or other flooring 2 infany convenient way and provided with a steam coil 3 located adjacent the bottom i of the tank to which steam may be applied by a steam pipe 5 controlled by a valve 6.. The coil may be of any suitable construction and either entirely closed or else provided with perforations 8 as shown. It is found in practice, however, that substantially equally good results are obtained through the use of a closed coil effective 'to heat the contents of the tank by radiation alone, as by the use of a perforated coil effective to heat by radiation supplemented by jets of live steam liberated into the contents of the tank. The tank may also be provided with a suitable liquid gage 10 whereby the height of the liquid may be easily deter mined by observation and also with an outlet pipe 12. communicating with the interior of the tank through the bottom and preferably passing downwardly therefrom, thence in a horizontal direction, and thence vertically upward to a suitable height above the floor '2 where it is curved over and arranged to discharge into a hopper or funnel 13, the end of. the pipe terminating a short distance above the mouth of the hopper so that the liquid. flowing from the pipe may be readily observed by the operator of the apparatus. From the hopper 13 a pipe 14; is arranged to discharge the liquid to any desired point in preparation for such further treatment as may be desired which treatment forms no part of the present invention. For regulating the'fiow of glue solution-in the tank, the pipe 12 may be provided with a suitable, conveniently positioned valve 15, andto facilitate continuous testing of the solution a suitable test tube 17 may be located above the valve or in any other suitable position connected with pipe 12 by smaller pipes 18 and supplied with.a hydrometer 20, the parts being arranged in suchmanner that as the glue solution flows throughpipe 12 a part of it will be bypassed through pipes 18 into the test tube 17 where its density may conveniently be ascertained. A large drain pipe 21 provided with a valve 22 may also be provided for draining the tank.

Positioned within the tank 1 and at a suitable distance above the bottom lthereof, is a preferably circular false floor 25 conveniently supported on beams or posts 26 so as to afford a space or chamber 27 between the bottom 4 and the under side of the false floor 25, which is provided with a plurality of suitable holes or apertures 28 and, preferably' atv its center, with a vertically posi- 'tioned stand pipe 30 of sufficient length to extend above thetop of the tank for a suitable distance. This pipe may be of any convenient diameter, is preferably considerably enlargedadjacent its lower end, for a height -o'f several inches as clearly shown in Fig. 1, and is'providedwith a flange 33 whichmay be conveniently secured: as by bolts or nuts 34L, 35 to the false floor 25, in which is formed an opening 38 corresponding with the opening in the end of the pipe. A valve 40 may be located in the pipe above the top of the tank, and beyond the valve a plurality of holes or apertures 41 are drilled or otherwise formed in the walls of the pipe preferably substantially normal to its axis, the upper end of the pipe being closed and provided with a downwardly curved,.preferably circular baliie plate 42 of a size and shape suitable for deflecting liquid issuing from the apertures 11 and distributing the same over the surface of the contents of the tank.

The false floor 25 may preferably be of a somewhat less diameter than the interior of the tank adjacent thereto, so that'an annular opening 15 will be left between the periphery of the floor and the wall of the tank. Suitably secured to the periphery of the former, is a screen 50 of wire netting or other suitable material, the sides of which are inclined upwardly and inwardly so that the netting will present the appearance of a hollow truncated cone, the upper end of which is open and the lower end of which is closed bythe false floor 25. To assist in holding the netting in position, a plurality of supports or battens 51 are provided and secured to the walls of the tank andt'o the screen, the battens being widerat the'top than at the bottom and positioned vertically and radially in the tank at suitable distances around the interior thereof, as clearly shown in Fig. 2.. The spaces between the battens may preferably be filled before the tank is charged with the material from which the glue to be extracted, as hereinafter described, with suitable filtering material 55, and in practice I have found that this material may be conveniently consists of excelsior, coke, hair or the like, and in fact, that any cheap material adapted tofill up the spaces between the battens while allowing the glue solution to percolate downwardly therethrough may be conveniently used for this purpose. I V

For the purpose of directing a jet of air or other gaseous medium. or fluid upwardly in the pipe 30 from a point adjacent the lower end thereof, suitable means are'provided which may preferably comprise an upwardly directed nozzle 60 positioned within the enlarged portion of the pipe and connected, as by a pipe 61 extending un'derthe flalse floor 25 and passing through th'e wall of the tank. with a suitable source of compressed air or other fluid notshown, a valve 62 conveniently positioned in =thepipe 61 serving to control the How of air-from the nozzle.

My improved process'forthe extraction-of glue, gelatin and the like may be practised, when utilized; in an apparatus constructed substantially as herebefore described, either as an intermittent process, in which case the treatment of the glue stock is interrupted when the li uid has acquired the desired glue content an d all or a portion of the extracted liquid withdrawn, fresh liquid substituted and the process continued till this liquid reaches a similar concentration when it is withdrawn and fresh liquid again supplied, these operations being repeated until all, or substantially all, of the colloidal matter in the glue stock is extracted, or the process may be practised as a continuous one, in which the treatment of the glue stock is carried on continuously until all, or substantially all, of the colloidal matter is extracted.

In carrying out the process the spaces between the battens having been packed with excelsior or other material 55, and all valves being preferably closed, the tank is filled, preferably nearly to the top, with a charge of glue stock which may comprise hides, skins, bones, ossein, or other animal refuse capable of yielding the desired colloidal matter, and a su'liicient amount of water or other liquid then introduced into the tank to fill the space 27 and preferably rise for several inches above false floor 25, the exact amount of water supplied depending on the nature and quality of the stock. Steam is next introduced to the coil 3 in a sufficient amount to gradually raise the temperature of the liquid in the vicinity of the coil, and simultaneously a relatively small quantity of air is permitted to issue from the nozzle 60, which, probably in conjunction with the natural tendency of the heated liquid in the vicinity of the nozzle to rise, causes an upward circulation in the pipe 30, valve 40 of course having been opened, from whence the heated liquid finds outlet through the holes ll and with considerable force impinges on the under side of the baflie plate and is thereby deflected back over the contents of the tank. Thereafter the liquid gradually percolates downwardly toward the bottom of the tank, effecting a gradual lixiviation of the contents and, arriving in chamber 27, is reheated and again ascends pipe 30 along with the air which continuously isues from the nozzle so that a constant circulation of the liquid in the tank is effected.

As in the process disclosed in my said applicationSerial No. 307,369 the local heating of the liquid is solely depended upon to effect the cyclic circulation, it is requisite when utilizing that process to maintain the temperature of the liquid sufiiciently high to obtain the desired effect but since, in the present process, the natural tendency of the heated liquid to rise is supplemented by the action of the air issuing from the jet, the liquid may be maintained at practically any ing from approximately 140 F. upwardly t0 the boiling point, only a relatively small amount of air is necessary.

The treatment of the glue stock is continued for a suitable period which in practice is found to vary ordinarily from an hour and a half to two hours from the time when the heat is first applied until hydro1n- 'eter readings of the solution in the tank show the same as containing the desired dry glue content, for example, a dry glue con- 0 tent of approximately 4%. The heat and air may now be shut off and the liquid contents of the tank drained through pipe 21, or in any other convenient way, fresh water or other extracting liquid supplied to the contents of the tank, the heat and air again turned on and the glue stock treated a second time in a similar manner, these operations being repeated until all,or substantially all, of the colloidal matter has been extracted, after which the solid residue is removed from the tank and a fresh charge of glue stock introduced. However, it is frequently desirable or convenient to operate the process as a continuous one, in which case, instead of withdrawing all of the liquid when it shows the desired dry glue content, the valve 15 may be opened to permit only a portion of the solution to pass off from the tank at a moderate speed, determined by the size of the container and the quantity of the contents thereof. It will be found that the dry glue content in the liquid withdrawn from the tank will slowly increase as the treatment of the glue stock is continued, until a point is reached, for example when the solution shows a glue content of say, substantially 6%, when it may be desirable to add more water to the contents of the tank. which operation may be readily effect ed by a suitable tap positioned to direct the water into the tank. From this point in the process the amount of water added should preferably approximate the amount of liquid drawn off, due allowance being made for the addition of water from the condensation of live steam if same is supplied from the coil 3. The rates of drawingoff of solution and of addition of fresh water may be readily regulated so that the dry glue content of the solution flowing through the pipe '12 will remain substantially constant, for example, at a dry glue content of approximately 6%, and this condition of operation having been obtained. the process may be continued unchanged until it is found by test that the dry glue content in the liquid is falling materially below the desiredamount, for example, to approximately 4%. When this condition is reached, no more fresh water should be introduced into the tank, but the heat and air may preferably be continued to be applied,

and the circulation of the liquid contents .of the tank kept up, until it is found that described certain methods of carrying out the process the sub ect of my invention, the

same are only illustrative and may frequently be conveniently modified in various particulars to meet varying conditions, and

it will further be noted that in the carrying out of the process, no manual or mechanical agitation of the contents of the tank is required or employed, the circulation of the liquid therein induced being suffiicent to effect the extraction of the maximum quantity the ch amber 2 of glue or gelatin from the glue stock.

It has been found in practice that during the treatment of certain classes of glue stock .there is a tendency toward the formation of a relatively impermeable cake at the bottom of the mass, which tends to clog the holes in the false floor, and thereby impede the passage of the liquid. However, in an apparatus constructed as hereinbefore described, a constant. and adequate circulation of the liquid is insured, for while a certain amount of the cake may form adjacent the surface of the false floor 25, there seems but little tendency for the cake to form on the surface of the screen 50, while suchamounts as do form thereon are immediately washed off by the downwardly percolating liquid which is constantly passing' through the screen and thence through the holes 28 and annular opening 45, into 7. It seems probable that the prevention of the formation of the cake in the screen is largely due to its inclination. making it difficult for the cake form.- ing ,matter to adhere thereto, and further that the filling of excelsior, coke or other material around the screen while presenting a considerable surface for the glue stock to .rest upon affords, nevertheless, an infinite number of apertures through which the liquid can percolate, so that even though the cake forms somewhat thickly at certain points thereby temporarily diminishing the percolation inthat vicinity, there {are always other points where it can take place with sufficient freedom to insure a return of enough liquid to chamber 27 through the several passages thereto to keep up a constant circulation in the tank,

so ,long as suflicientheat is applied.

vVhile l have illustrated and described herein one form of apparatus suitable for carrying out my process for the extraction of glue, gelatin and the like, I do not thereby desire or intend to limit myself specifically thereto, as various modifications and changes may be made therein if desired. Furthermore, while I have described with considerable particularity certain methods of performin the process itself, and have given certain examples and percentages by way of illustrating the same, I do not thereby desire or intend to limit orrestrict the scope of my invention in any way, as suitable modifications and variations may be made in the steps employed in carrying out the process; fluids other than air may be employed in effecting the circulation; the process may be practised either as an intermittent or continuous process, and the percentages hereinbefore given by way of example merely may be varied to adapt the process for use with different kinds of glue or gelatin stock, or for the production of glue, gelatin or the like of different grades or qualities, or to meet the varying conditions encountered in difierent manufacturing establishments as desired, without departing from the spirit and scope of the invention as defined in the appended claims.

Having thus described my invention, 1 claim and desire to protect by 'Letters Patent of the United States:

An apparatus for the extraction of glue; gelatin and the like comprising an open tank having a perforated false floor spaced from the bottom and sides thereof, a standpipe extending from said floor to a point above the top of the tank and having openings and a deflecting means adjacent its upper extremity, means for withdrawing liquid from the tank. heating means between said false floor and the bottom of said tank, 7

a screen. disposed around the peripheral edge of the false floor and inwardly inclined with respect thereto, and means adjacent the bottom of said standpipe adapted to direct a column of fluid upwardly therein.

rREnERIc H. TUNNELL. 

